gcc11: downgrade to 11.2.0 also on x86_64-darwin

https://hydra.nixos.org/build/175546330

pkgs/development/compilers/gcc/11/default.nix

@@ -56,7 +56,8 @@ let majorVersion = "11";
     # updated version is not available. Keep aarch64-darwin on 11.2.0 so the
     # large body of packages which depend on gfortran are still functional
     # until GCC 12 is the default.
-    version = if (stdenv.isDarwin && stdenv.isAarch64) then
+    # On x86_64-darwin, building libgcc suffers from some different issues with 11.3.0.
+    version = if stdenv.isDarwin then
       "${majorVersion}.2.0" else "${majorVersion}.3.0";
 
     inherit (stdenv) buildPlatform hostPlatform targetPlatform;
@@ -96,7 +97,7 @@ stdenv.mkDerivation ({
 
   src = fetchurl {
     url = "mirror://gcc/releases/gcc-${version}/gcc-${version}.tar.xz";
-    sha256 = if (stdenv.isDarwin && stdenv.isAarch64)
+    sha256 = if stdenv.isDarwin
       then "sha256-0I7cU2tUw3KhAQ/2YZ3SdMDxYDqkkhK6IPeqLNo2+os="
       else "sha256-tHzygYaR9bHiHfK7OMeV+sLPvWQO3i0KXhyJ4zijrDk=";
   };